complete lack of maturation. Most superficial layers show parakeratosis.
Mitoses can be recognized at all levels (H&E x HP).
The number of abnormal cells in cellular samples is usually
greater in cases of carcinoma in situ than in dysplasias. The cel-
lular changes of importance in the recognition of cancer in situ
are those exhibited by cells desquamated or forcibly scraped
from the epithelial surface.
Arrangement of Cells.
Carcinoma in situ, because of the undif-
ferentiated nature of the component cells, lacks the characteris-
tic cytoplasmic changes of differentiation (maturation). Either
the cells are isolated or, because of a disturbance in cytoplasmic
division during cell division, are adherent together and arranged
as syncytial aggregates (Figs. 8.83 and 8.84). Most samples do
contain isolated cells, but aggregates of abnormal cells predomi-
nate. A scraping of the cervix forcibly removes cells from the
surface. In view of the high number of cells arranged in syn-
cytial masses, in these situations, taking a smear is essentially
performing multiple microbiopsies. In a syncytial group, cells
are arranged irregularly and have indistinct cell borders and
overlapping nuclei (Fig. 8.85). The latter two features differen-
tiate these syncytial aggregates from sheets found in the pres-
ence of dysplasias and in which the more distinct cell borders
and the more regular arrangement of the cells are a reflection of
Fig. 8.83 Carcinoma
Cells occur singly but predominantly in
syncytial aggregates with indistinct cell borders. Cells have only a minimal
amount of cytoplasm. Nuclei, although relatively small, vary greatly in size
(Papanicolaou x MP).
Fig. 8.84 Carcinoma
Syncytial aggregate of cells with indistinct
cytoplasmic borders. Nuclei vary in size and shape and are frequently
overlapping. Nuclear chromatin is hyperchromatid, irregularly distributed,
and coarsely granular (Papanicolaou x OI).